Caster.



R. E. TOMPKINS.

CASTER.

APPLICATION FILED SEPT- 4. I914.

Patented. Apr. 13, 1915.

avwmvtoz RETOMPKINS RICHARD EUGENE 'I'OMPKIINS, 0F DANBU'RY,CONNECTICUT.

(EASTER.

Specification of Letters Patent.

Patented Apr. f3, 1915.

Application filed September 4, 1914. Serial No. 860,277.

tion, reference being had to the accompanying drawings.

This invention relates to new and useful improvements in casters, andparticularly ball bearing casters.

An object of this invention is the provision of a caster which comprisesa caster ball which is partially inclosed within a casing,

the caster ball being maintained in spacedrelation from the interior ofthe casing by a series of bearing balls.

A further object" of this invention is the provision of a caster whichcomprises a. caster ball partially inclosed within a casing, the casingbeing formed to provide a pair of race ways to receive bearing balls,the bearing balls being arranged above and below the horizontal axis ofrotation of the caster ball. 7

With these and other objects in View, my invention consists in thenovelconstruction, combination, and arrangemenfiof parts, to behereinafter more fully described, claimed, and illustrated in theaccompanying drawing, in which Figure 1 is a vertical sectional View ofmy improved caster; and Fig. 2 is a bottom plan view thereof.

Referring more particularly to the drawing, the numeral 1 designates ahollow casing which is provided at its lower end with an inwardly curledflange 2, the flange providing a race way for an annular series ofbearing balls 3. A caster ball 4 is disposed within the casingithroughits upper end, and

as the distance etween opposite points of the edge of the flange 2 isless than the length of the axis of the caster ball 4:, the,

main portion of the caster ball is inclosed within the casing with aportion thereof projecting below the casing, the ball at a point belowits horizontal axis of rotation engaging the series of bearing balls 3.The casing 1 adjacent its upper end vis bulged outwardly as at 5 toreceive an annular series of bearing balls 6, the balls 6 beingrelatively larger than the balls 3, and engaging against the caster ball4 above the horizontal axis of rotation thereof.

A cap 7 is provided to close the upper end of the casing 1, the capbeing provided on its under face adjacent the marginal edge thereof withan annular groove 8, to receive the upper edge of the casing. The groove8 is oftsuflieient length to entirely inclose the portion of the casingwhich projects upwardly from the bulged portion 5 thereof, so that theupper edge of the casing engages against the'upper wall of the groove,and the lower face of the cap outwardly of the groove bears against thebulged portion 5 of the casing. Formed in the cap 7 are threadedopenings 9 which are adapted to register with openings 10 which areformed in the casing above the bulged portion there- I of, theregistering openings being adapted to receive set screws 11, whereby thecap is secured in position to close the u per end of the casing. Theunder face 0 the cap 7 which is disposed within the casing is providedwith an annular groove 12 which groove in conjunction with the bulgedportion 5 of the casing comprises a race way for the series of balls 6to hold the same closely engaged against the caster ball 4. Formedcentrally in the cap 7 is a vertical angular opening 13 through whichthe angular portion 14 of the head of an upwardly extending screw 15 isadapted to pass, the extremity of the head of the screw being swagedagainst the under face. of the cap, and by providing the angular portion14 which engages in the angular opening, relative turning of the screwand casing is prevented.

From the above description taken in connection with the accompanyingdrawing, it will be seen that I have provided a caster in which thecaster ball is entirely spaced from the casing by a series of bearingballs, in which manner friction is reduced to a minimum. It will be seenthat the cap 7 holds the various parts of the device in their respectivepositions, and should one of the bearing balls become broken, it ismerely necessary to disengage the set screws 11 from their engagementwith the casing and the cap so that the casing may be disengaged fromthe cap and the broken ball replaced by a new one without the necessityof removing the screw 15 from the article of furniture in which it isengaged.

My improved caster is easily assembled, by inverting the casing andplacing the ball 4: therein, so that the series 3 of the smaller bearingballs may be dropped in the casing against the caster ball, so that whenthe caster ball is moved to its outermost position, the balls 3 aremaintained in the curled flange 2. When the caster ball 4' and thebearing balls3 are in this position, the casing may be turned to itsproper position, whereupon the bearing balls 6' may be dropped into thecasing, the balls striking the surface of the caster ball 4 and readilyfinding their positions within the bulged portion 5 of the casing. Whenthe cap 7 is placed in its proper position to close the upper end of thecasing and secured thereto, the caster is ready to be applled to anydesired article of furniture tosupport the same on the floor, and as thecaster ball is the only portion of the device which engages in therace-way, a caster ball arranged in the casing and adapted to rest uponsaid bearing balls, a portion of the caster ball being extended throughthe lower end of the casing, said casing being provided adjacent itsupper end with an outwardly projecting bulged portion, a series ofrelatively larger bearing balls arranged within the bulged portion ofthe casing to engage against the caster ball at a point above itshorizontal axis of rotation, a cap havinga groove formed in its underface adjacent its marginal edge, whereby to receive the upper end of thecasing, screw members extending through the other wall of the cap andthe upper end of the casing, for detachably securing the cap to thecasing, and the underface of said cap within the casing having a grooveformed therein, said groove in con- ]unction with the bulged portion ofthe casing forming a raceway for the larger bearing balls, to hold thesame in engagement with the caster balls.

In testimony whereof I hereunto affix my signature in the presence oftwo witnesses. RICHARD E. TOMPKINS.

Witnesses:

GEono J. MILLER, EDWARD O. NEWTON.

